Diddy caused a big commotion outside the most swanky place in L.A. today ... well, it was actually Diddy's car that triggered a guns-drawn response by L.A. County Sheriff's deputies.

We've learned Diddy had just been dropped off at the Soho House ... an ultra-exclusive, private club in West Hollywood.  Diddy's bodyguard and another person drove Diddy's $500,000 Maybach away from Soho, but they didn't get far.

We're told someone called 911 and said someone inside the Maybach had a gun.  At least 9 squad cars roared to the scene.  Cops pulled their guns and ordered the occupants of the Maybach out of the car and made them lie prone on the ground, until they discovered there weren't any guns. 

The street was closed down temporarily until deputies gave the all-clear.